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Power Factor Correction and Capacitor Current Calculator

Estimates required capacitor-bank kvar to move a load from an entered initial power factor to a target power factor, and estimates three-phase line current for that bank. Harmonics, resonance, switching steps, tariff requirements, and motor self-excitation are outside this calculation and require engineering review.

Inputs

Range: at least 0.01 kW

Example starting value: 100 kW. Replace it with the measured operating load.

Range: 0.01–0.99

Enter the measured or documented displacement PF before correction as a decimal between 0.01 and 0.99.

Range: 0.01–0.999

Enter the desired displacement PF as a decimal. It must exceed the initial PF for a capacitor recommendation.

Range: at least 1 V

Enter the RMS line-to-line voltage at the capacitor bank connection. This calculator currently sizes current for a three-phase connection.

Result

Estimated three-phase line current
50.68 A
Initial reactive power (kvar)
75.00 kvar
Estimated capacitor bank size
42.13 kvar
Target reactive power (kvar)
32.87 kvar
Target PF is above initial PF
Estimated capacitor bank size
\begin{cases}\mathrm{Real\ power\ (kW)} \cdot (\mathrm{Initial\ Tangent} - \mathrm{Target\ Tangent})&\text{if }\mathrm{Target\ power\ factor} > \mathrm{Initial\ power\ factor}\\0&\text{otherwise}\end{cases}
\begin{cases}100 \cdot (0.75 - 0.32868410517886)&\text{if }0.95 > 0.8\\0&\text{otherwise}\end{cases}
Estimated three-phase line current
\frac{\mathrm{Estimated\ capacitor\ bank\ size} \cdot 1000}{(\mathrm{Phase\ Factor} \cdot \mathrm{Three\-phase\ line\ voltage\ (V)})}
\frac{42.131589482114 \cdot 1000}{(1.7320508075689 \cdot 480)}

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